HTS filters have many applications in telecommunication, instrumentation and military equipment. The HTS filters have the advantages of extremely low in-band insertion loss, high off-band rejection and steep skirts due to the extremely low loss in the HTS materials. In one design, the HTS filters are comprised of spiral resonators that are large in size. In fact, at least one dimension of the resonator is equal to approximately a half wavelength. For low frequency HTS filters with many poles, the regular design requires a very large substrate area. The use of self-resonant spiral resonators to reduce the size of the HTS filters and solve cross-talk and connection problems reduces the size of the substrate area required. Nevertheless, the substrates of thin film HTS circuits are special single crystal dielectric materials that have a high cost. The HTS thin film coated substrates are even more costly. The mini-filter design must then be created on the HTS film typically using photoresist and ion etching techniques. The final cost is significant and it is commercially important to have a high yield of mini-filters that meet specifications.
HTS coils have applications as transmit, receive, and transmit and receive coils for electromagnetic signals. Producing these HTS coils requires the same steps that are used in producing the HTS filters. The related costs are also similar so that it is important to have a high yield of HTS coils that meet specifications.
U.S. Pat. No. 5,262,394 discloses a ceramic superconductor comprising a metal oxide substrate, a ceramic high temperature superconductive material, and an intermediate layer of a material having a cubic crystal structure. There nevertheless remains a need for a process for producing in high yield mini-filters and coils that meet required specifications, and the mini-filters and coils so produced.
An object of the present invention is to therefore provide a process for producing in high yield mini-filters and coils that meet required specifications.